On an aircraft, a nacelle is used to house an engine and a thrust reverser which can be of the cascade or pivoting type, among other types. FIGS. 1A-1B illustrate a typical gas turbine engine inside a nacelle 22, which is attached via a pylon 21 to an aircraft wing 20. The nacelle 22 includes a forward fixed structure 23 and an aft fixed structure 12. The aft fixed structure 12 includes a thrust reverser.
A main jet stream F1 flows through the nacelle 22 from an approximate right-to-left direction in FIGS. 1A-1B. Whereas FIG. 1A shows the thrust reverser operating in a stowed state/mode, FIG. 1B illustrates the thruster reverser operating in a deployed state/mode with a radially outward deflected jet F1′ exiting doors 1 which pivot on two pivot bearings 27 (FIG. 1A), provided in lateral side beams 2 (FIG. 1A) which bound an opening 26 (FIG. 1B).
FIG. 1C provides additional details regarding a portion of a thrust reverser 82 (which may be incorporated in the nacelle 22 of FIGS. 1A-1B). As shown in FIG. 1C (which is representative of a thrust reverser operating in a stowed state/mode), a flow channel 53 is formed between a first wall (e.g., an inner wall) 51 and a second wall (e.g., an outer wall) 52. Arrows 54 represent a flow of air in the flow channel 53; the air flow 54 is generally in a left-to-right direction in FIG. 1C and may correspond to the main jet stream F1 of FIGS. 1A-1B. The wall 52 has associated therewith an inner surface 55 that is proximate/adjacent to the flow channel 53. The thrust reverser 82 includes a blocker door 56 (which may correspond to the doors 1 of FIGS. 1A-1B). An axis of rotation for the blocker door 56 is shown as reference character 57. An actuator 58 is used to control/drive the deploying or stowing of the blocker door 56. The blocker door 56 includes a front deflector 59 and an inner surface 60. The components/devices that have been described form a flow line 61 of the channel 53 and also form a flow cavity 62. Superimposed in FIG. 1C are reference characters 70, 71, and 72; reference character 70 is representative of an articulation point for the actuator 58, reference character 71 is representative of a fixed connection/coupling between the actuator 58 and the blocker door 56, and reference character 72 is representative of a resting lip for the front deflector 59.
The contour/shape of the flow channel 53 has a significant impact on operational parameters. For example, it is generally desirable to have a smooth flow line 61. However, the cavity 62 has been shown to contribute to total pressure losses, due at least in part to secondary flows recirculating behind the blocker door 56. The pressure losses lead to degraded performance in terms of, e.g., specific fuel consumption (SFC).